Experimental Study On Topical Cryotherapy For Fungal Corneal Ulcer

Objective1. To investigate the ultrastructure changes of fungus treated with cryotherapy inrabbit with fungal corneal ulcer. Therefore，to help clinical trial by providing withexperimental datas.2.To evaluate the efficacy of cryotherapy on rabbits’s fungal corneal ulcer bycontinuous microscopy.Methods1. In developing animal models，the rabbits were randomizely divided into threegroups—fusarium，aspergillus and candida groups. In each group，the diseases wereclassified into mild，moderate and sever infections.2. For the treatment，the rabbits were randomizely separated into two group—experimental group（cryotherapy combined with drug）and control group （drugonly）.3.Before cryotherapy or On the first day after cryotherapy， three rabbitsrespectively were killed for ultrastructure observation of fungal ulcer by transmissionelectron microscope（TEM) and scanning electron microscope（SEM)4.Confocal microscope（IVCM) examinations were conducted on the seventh，fifteenth and thirtieth days after cryotherapy to evaluate the efficacy of cryotherapy onfungal corneal ulcer.Results1. The ultrastructure of fungus and hypha were observed by SEM and TEM inPre-operation and post-operation.（1） Results of SEM：Pre-operation: The structure of fungal cell wall and cell membrance was integrated;and the electronic density of structure was high. Post-operation：The electronic density of structure became low，the form of fungalcell wall and cell membrance became irregular；The cell nucleus was dissolved and thehypha was fragmented.（2）Result of TEM：Pre-operation: normal fungus was quasi-circular，the cell wall and cell membranewere continuous，and uniformity was integrated.Post-operation：The continuity of cell wall and of cell membrane was broken，thenucleus and cytoplast were dissolved.2. The dynamic observation of the effects and course of disease was seen byconfocal microscope.（1）Courses of disease were differentiated as following:Control group: The result of control group was average from21.65days to38.67day.Experimental group: The result of control group was average from9.45days to18.05days.(2) Curative effect rate were differentiated as following:Control group: Curative effect rate was about34.5%.Experimental group: Curative effect rate was about74%.From above, it suggested that the curative effect was significant differentebecause P＜0.01.ConclusionTopical cryotherapy for fungal corneal ulcer of rabbits was significantly effective.Meanwhile，there were different curative effect in different pathogenic bacterium asfollowing:curative effect of candida was the best of all，and curative effect of aspergillusfusarium was the worst.